Glutamic Acid

We confirmed this ingredient's definition and its registered function in public regulatory databases, but found no published study data on how the ingredient itself acts on the skin (checked by KAIAN, September 2026). We will update this page if new reports appear.

An acidic amino acid regarded as a precursor of PCA (pyrrolidone carboxylic acid), a major component of the stratum corneum's natural moisturizing factor (NMF); formulated to condition the skin

An acidic amino acid with two carboxyl groups. A measurement study of human stratum corneum describes the NMF component PCA as a metabolite of glutamic acid (a review describes PCA as formed from glutamine). Whether topically applied glutamic acid is converted to PCA in the stratum corneum, and human studies showing a moisturizing effect of glutamic acid alone, were not confirmed (uptake into isolated corneocytes has been reported in vitro)

No public data on typical concentrations in cosmetics could be confirmed (varies by product)

No public data on the time to a perceptible effect with topical use could be confirmed

Ingredient-specific irritation data not confirmed. The US CIR Expert Panel concluded that α-amino acids are safe as cosmetic ingredients under the practices of use and concentration assessed (2013; whether this ingredient was among those assessed is unconfirmed)